Reconstituted-tobacco smoking materials

ABSTRACT

A smoking material comprises a tobacco component consisting of or comprising a combustible reconstituted tobacco, which smoking material contains a filler intimately incorporated therein and consisting solely or largely of carbon. The carbon employed is in finely divided form and of a particle size less than 150 microns. Adhesion between the carbon particles and the tobacco is effected without extraneous adhesives and by substances released in slurrying the tobacco used. Preferably the reconstituted tobacco consists solely or essentially of natural tobacco substances. It may contain added tobacco extract as well as tobacco solids.

United States Patent [1 1 Hedge et al.

11] 3,805,803 [4 1 Apr. 23, 1974 [73] Assignee: Brown & Williamson Tobacco Corporation, Louisville, Ky.

[22] Filed: May 24, 1972 [21] App]. No.: 256,410

[30] Foreign Application Priority Data June 11, 1971 Great Britain 27523/71 [52] 11.5. CI. 131/140, 131/17 [51] Int. Cl A24b 15/04 [58] Field of Search 131/2, 15, 17, 140-144 [56] References Cited UNITED STATES PATENTS 10/1963 Reynolds et al. 131/17 9/1971 Briskin et al 131/2 3,203,432 8/1965 Green et al. 131/140 C 3,025,860 3/1962 Grossteinbec'k et al. 131/140 C FOREIGN PATENTS OR APPLICATIONS 437,092 5/1967 Switzerland 131/17 R Primary Examiner-Melvin D. Rein Attorney, Agent, or Firm-Finnegan, Henderson, Farabow & Garrett [5 7] ABSTRACT A smoking material comprises a tobacco component consisting of or comprising a combustible reconstituted tobacco, which smoking material contains a filler intimately incorporated therein and consisting solely or largely of carbon. The carbon employed is in finely divided form and of a particle size less than 150 microns. Adhesion between the carbon particles and the tobacco is effected without extraneous adhesives and by substances released in slurrying the tobacco used. Preferably the reconstituted tobacco consists solely or essentially of naturaltobacco substances. It may contain added tobacco extract as well as tobacco solids.

1 Claim, No Drawings RECONSTITUTEDTOBACCO SMOKING MATERIALS This invention concerns improvements relating to reconstituted-tobacco smoking materials.

According to the invention, a smoking material comprises a tobacco component consisting of or comprising a combustible reconstituted tobacco, which smoking material contains a filler intimately incorporated therein and consisting solely or largely of carbon. Preferably the reconstituted tobacco is of a type which consists solely or essentially of natural tobacco substances. Advantageously, the filler is added to the tobacco component before it is made into web, sheet or filaments and so that the filler becomes incorporated within the fibrous structure of the reconstituted tobacco.

The proportion of filler included should amount to at least 1 percent and preferably to at least 5 percent by weight of the smoking material. Up to 50 percent of filler may be included, but the upper limit in practice will depend upon the nature of the product, particularly its mechanical strength. Carbon should not be present in such a large proportion as to weaken excessively the shreds or filaments of the smoking material as used. The particle size of the carbon is preferably less than 150 microns.

Reconstituted tobaccos of the aforesaid type preferably to be used are characterised essentially by the absence of extraneous adhesives, binding being achieved by substances of, or released from, natural tobacco. Such reconstituted tobaccos are also to be distinguished from those in which the originating material is pulped chemically, using nitric acid or caustic soda for example.

Reconstituted tobacco may be made without nontobacco adhesive by several known methods:

1. For example, as described in US. Pat. specification No. 3,043,723, reconstituted tobacco may be produced by disintegrating hot-water-extracted tobacco parts, mixing the extracted tobacco parts as binder with tobacco fines such as lamina or midribs, reducing the particle size of the mixture and casting a sheet on a solid band, for example of stainless steel, and evaporating the water.

In this case, carbon in fine granular form can be added together with the tobacco fines to the binder prepared from the water-extracted tobacco parts.

2. Filamentary reconstituted tobacco may be produced by extruding a mixture of water and tobacco parts comminuted to powder form, as described in US. Pat. specification No. 3,203,432.

The carbon can be added to the comminuted tobacco prior to the addition of the water and subsequent extrusion.

3. According to another method, reconstituted tobacco may be produced by laying a web of fibres, obtained by pulping tobacco material, on a Fourdrinier machine. The web may or may not be impregnated with concentrated aqueous tobacco extract.

The carbon can be added to the stock supplied to the machine.

The present invention can be applied with advantage to reconstituted tobacco of any of these kinds.

Examples of ways of carrying the invention into effect will now be more fully described:

EXAMPLE 1 (METHOD 1 ABOVE) Reconstituted tobacco was produced in the following manner:

Binder was obtained by cooking 200 lbs of threshed Burley stem in 200 gallons of water for 1 hour under a pressure of 30 lbs per square inch, this being followed by washing with hot water. The solubles were rejected and the residue was hammer milled in a Rietz mill (One pass, 0.063 inch screen and two passes, 0.027 inch) at a consistency of 3 percent. Finally the resultant stock was homogenised by six passes under a pressure of 2,000 pounds per square inch at a consistency of 2.14%.

A tobacco flour was produced from a blend of factory shorts from blended cigarette manufacture by milling to a size of percent less than microns. This flour (with 8.3% moisture content) was mixed with the binder (with 2.14% solids) in a proportion of 3:1 dry weight, in one case without the addition of carbon and in other cases with 3.5% and 7% (based on the total dry weight) respectively of activated carbon of a particle size less than 150 microns, plus 5% (with reference to the flour, or flour and carbon) of glycerol as humectant. The mixing was performed in a high-speed mixer at 90C for 10 minutes. The three resultant slurries were cast as sheets and dried on a stainless-steel band.

.Total Particulate Matter in Smoke Total Nicotine Alka- Carbon Content loids in Smoke mg per Reduction mg per Reduction cigarette Cigarette 0 24.0 1.4 3.5 22.6 6 L2 14 7.0 18.2 24 0.98 30 The reductions are larger than would be expected from the dilution represented by the contents of filler.

EXAMPLE 2 (METHOD 2):

Carbon was added in proportions of 10 and 20% to a reconstituted tobacco produced as described in the aforesaid specification U.S. Pat. No. 3,203,432, sometimes known as Batex, in which ground tobacco is extruded under high pressureto form coherent filaments similar to cut tobacco in cross section. Cigarettes were prepared from 50/50 mixtures of the reconstituted tobacco and a flue-cured tobacco blend and were smoked in substantially the manner described above with the following results:

Carbon Content Total Particulate Matter in Smoke in Reconstituted mg per Cigarette Reduction Tobacco The reductions are larger than would be expected from the dilution represented by the contents of filler.

EXAMPLE 3 (METHOD 3):

Threshed Burley stem was cooked at 90-95 C for 3 30-minute periods, with a stem/water ratio of 1 to 10 by weight, followed by draining after each cook. The fibrous residue was then passed through a disc mill at 16.5% consistency, the clearance between plates being 0.035 inches, this being followed by beating in a conventional Valley beater for 20 minutes at 2% consistency.

The resultant stock was dilted to' 0.6% consistency and fed together with finely divided activated carbon, of which 100% was of a size less than 150 microns, to the head-box of a conventional Fourdrinier papermaking machine of the tissue-paper type. A continuous sheet with a final thickness ofO. 13 to 0.23 mm was produced. Because of the low retention of carbon, in relation to fibres, on the Fourdrinier wire, the ratio of carbon to fibres fed to the headbox will generally be two to three times the ratio required in the final sheet material.

Two series of samples of reconstituted tobacco thus prepared were used for tests. In a first series, A, the sheet material was impregnated with concentrated aqueous tobacco solubles extracted in the cooking stages. In a second series, B, the solubles comprised only residual solubles remaining in the fibre. For the impregnation, the extract obtained as aforesaid was concentrated in a climbing-film evaporator to a solids concentration of 29 percent.

The sheet was shredded to a form smokable in cigarettes and cigarettes prepared from the shreds were smoked on a conventional machine as described above.

Analysis of the smoke for a variety of compositions 4 of the reconstituted tobacco gave the following results for the total particulate matter in the smoke:

" Total Particulate The reductions are again larger than would be expected simply from the dilution.

The smoke from cigarettes produced as described above was found to be agreeable.

We claim:

1. A method of reducing the total particulate matter from tobacco smoke to an extent greater than that expected from a tobacco dilution by a non-combustible filler means of equal mass, comprising intimately incorporating in a tobacco slurry finely divided carbon powder of a particle size less than 150 microns, said carbon consisting from about 10 percent to about 50 percent by weight of the composition and operative to achieve a reduction of the total particulate matter of from about 20 percent up to about percent, the binding of the carbon to the tobacco in the dried slurry being effected essentially without extraneous adhesives and by substances released from the natural tobacco per se. 

